Almost all base station antennas used for mobile communication up till now have, by design, more or less fixed characteristics. One exception is electrical beam tilt which is a frequently used feature. In addition some products exist for which beam width and/or direction can be changed.
Deploying antennas where characteristics (parameters) can be changed, or adjusted, after deployment is of interest since they make it possible to:                Tune the network by changing parameters on a long term basis        Tune the network on a short term basis, for example to handle variations in traffic load over twenty-four hours.        
Thus, there is a need to be able to adjust beam width and to adjust beam pointing direction to achieve these features.
Current implementations of these features are based on mechanically rotating or moving parts of the antenna which results in relatively complicated mechanically designs.